Differential medial temporal lobe morphometric predictors of item- and relational-encoded memories in healthy individuals and in individuals with mild cognitive impairment and Alzheimer's disease.
Differential medial temporal lobe morphometric predictors of item- and relational-encoded memories in healthy individuals and in individuals with mild cognitive impairment and Alzheimer's disease.
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健康个体以及患有轻度认知障碍和阿尔茨海默氏病的个体中项目和关系编码记忆的差异内侧颞叶形态测量预测因子。
DOI：
10.1016/j.trci.2017.03.002
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Goldberg,TerryE
中科院分区：
文献类型：
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作者：
Gomar,JesusJ;Ragland,JDaniel;Uluğ,AzizM;Sousa,Amber;Huey,EdwardD;Conejero-Goldberg,Concepcion;Davies,Peter;Goldberg,TerryE
情景记忆过程由内侧颞叶的不同亚区支持。与仅由海马支持的单一记忆识别模型相反，当前的模型表明，项目编码涉及嗅周皮层，而关系编码涉及海马旁皮层和海马。然而，这个模型还没有被检查的背景下，老化，神经退行性变，和MTL morphometrics. MethodsForty-four健康受试者（HS）和18个认知功能受损的受试者（9轻度认知障碍[MCI]和9阿尔茨海默病[AD]患者）进行了评估的关系和项目特定的编码任务（RISE），并进行了3T磁共振成像。RISE评估了关系记忆和特定项目记忆的差异贡献。FreeSurfer被用来获得MTL区域和海马volume.ResultsMemory的皮质厚度的措施，项目和关系记忆的准确性显着更好的HS组比MCI/AD组。在MCI/AD组中，关系记忆不成比例地受损。在HS中，分层回归表明，记忆预测项目编码后的围鼻厚度，海马体积关系编码后（均在趋势水平），并在关联识别的海马旁厚度显着。同样的脑形态测量学特征预测MCI/AD的记忆准确性，尽管对于项目编码，（R2 = 0.31）和海马体积和海马旁厚度的关系编码（R2 = 0.31）.讨论我们的结果支持情景记忆的模型，其中项目特异性编码与更大的嗅周皮层厚度相关，而关系编码与海马旁厚度和海马体积相关。我们不仅在HS中发现了这些关系，而且在MCI和AD患者中也发现了这些关系。在认知障碍的受试者中，海马体积的减少和关系记忆的损害尤为突出。
IntroductionEpisodic memory processes are supported by different subregions of the medial temporal lobe (MTL). In contrast to a unitary model of memory recognition supported solely by the hippocampus, a current model suggests that item encoding engages perirhinal cortex, whereas relational encoding engages parahippocampal cortex and the hippocampus. However, this model has not been examined in the context of aging, neurodegeneration, and MTL morphometrics.MethodsForty-four healthy subjects (HSs) and 18 cognitively impaired subjects (nine mild cognitive impairment [MCI] and nine Alzheimer's disease [AD] patients) were assessed with the relational and item-specific encoding task (RISE) and underwent 3T magnetic resonance imaging. The RISE assessed the differential contribution of relational and item-specific memory. FreeSurfer was used to obtain measures of cortical thickness of MTL regions and hippocampus volume.ResultsMemory accuracies for both item and relational memory were significantly better in the HS group than in the MCI/AD group. In MCI/AD group, relational memory was disproportionately impaired. In HSs, hierarchical regressions demonstrated that memory was predicted by perirhinal thickness after item encoding, and by hippocampus volume after relational encoding (both at trend level) and significantly by parahippocampal thickness at associative recognition. The same brain morphometry profiles predicted memory accuracy in MCI/AD, although more robustly perirhinal thickness for item encoding (R2= 0.31) and hippocampal volume and parahippocampal thickness for relational encoding (R2= 0.31).DiscussionOur results supported a model of episodic memory in which item-specific encoding was associated with greater perirhinal cortical thickness, while relational encoding was associated with parahippocampal thickness and hippocampus volume. We identified these relationships not only in HSs but also in individuals with MCI and AD. In the subjects with cognitive impairment, reductions in hippocampal volume and impairments in relational memory were especially prominent.